"Masked/Hidden" Weapons

I thought it'd be cool if there were hidden items. They would be a regular Flak Cannon, but maybe some sign at the end showing that it's more. A new artifact that "unlocks" the item would expose it and it would turn into a good magic item.

So you'd get a "Rocket Launcher ?" (question mark is the sign, like *)
Pick up/obtain the certain artifact (Weapon Unlocking Kit or something)
Adrenaline cost
boink, good magic weapon.

It would be very much like the magic weapon maker, except that you'd get a good weapon (+5 or above). It would be balanced by the fact that it will only work on "?" weapons. Maybe the artifact could "salvage" non-"?" weapons for an artifact, or maybe some kind of currency (if it's ever implemented

and yes, all of this is pretty much taken exactly from Guild wars